The game is a sort of a retelling of the 0079 story with battles that play like a game of galaxian!
There are different viewpoints that can be switched on the fly to any angle (from arcade-style to first-person, which gives you an optional gunsight), there are a couple of 2-player modes, and you get a separate sd g charger game on the same disc which plays the same as the main game.
SD Gundam: Over Galaxian is a semi-3D update of Namco's arcade classic Galaxian featuring the famous SD Gundam characters. The game plays pretty much the same as the original Galaxian, though there some added features such as a variety of power-ups. The game includes two different story modes (Gundam Story and G Changer Story), a remixed version of the original Galaxian, and a two-player VS mode. CG videos explain the story as you progress through the game.